有限时间观测器 ( FTDO) 是一种非线性观测器，近年来被广泛用于含高阶扰 动项非线性系统的控制器设计。但在以往的研究中，FTDO 仅能应用于具有仿射结构的 非线性系统且只能保证系统输出跟踪期望固定点。文中针对一类含有高阶非匹配扰动项 的非仿射纯反馈非线性系统的跟踪控制问题，提出了基于 FTDO 的非线性动态逆跟踪控 制方法。文中通过近似动态逆方法构建快变子系统，在慢时间尺度下将含有 FTDO 观测 输出的非仿射系统转换为具有仿射结构的线性系统，并追踪时变参考轨迹。该算法不依 赖于原系统的时标分离特性，并避免了反步法中的 “复杂性爆炸”问题。在 Matlab / Simulink 环境下的仿真结果表明，文中所设计控制器在被控系统具有非仿射结构时也能 准确估计高阶扰动项，且具有良好的跟踪性能。

Finite time disturbance observer ( FTDO) is a nonlinear disturbance observer which has been widely applied to controller designing for nonlinear systems with high-order disturbances． However，in the previous research， FTDO can only be applied to affined nonlinear systems and used to track a desired set-point． In this paper，a FTDO based nonlinear dynamic inversion approach was developed for the tracking control problem of a class of nonaffine pure-feedback nonlinear systems with high-order mismatched disturbances． A fast subsystem was established through the approximate dynamic inversion scheme． In the slow time-scale，the nonaffine system containing outputs of FTOD was transformed into a linear system with affined form to track the time-varying reference trajectory． The effectiveness of the proposed algorithm is independent to the time-scale split character of the original system，and avoids the problem of“explosion of complexity”in backstepping strategy． The simulation results on Matlab / Simulink environment demonstrate that the controller designed in this paper can accurately estimate high-order disturbances in the case of controlled system with nonaffine structure，and the tracking performance is good．